/*
 * QRious
 * Copyright (C) 2016 Alasdair Mercer
 * Copyright (C) 2010 Tom Zerucha
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/**
 * A basic manager for {@link Service} implementations that are mapped to simple names.
 *
 * @public
 */
class ServiceManager {

    /**
     * Creates a new instance of {@link ServiceManager}.
     *
     * @public
     */
    constructor() {
        this._services = {}
    }

    /**
     * Returns the {@link Service} being managed with the specified <code>name</code>.
     *
     * @param {String} name - the name of the {@link Service} to be returned
     * @return {Service} The {@link Service} is being managed with <code>name</code>.
     * @throws {Error} If no {@link Service} is being managed with <code>name</code>.
     * @public
     */
    getService(name) {
        const service = this._services[name]
        if (!service) {
            throw new Error(`Service is not being managed with name: ${name}`)
        }

        return service
    }

    /**
     * Sets the {@link Service} implementation to be managed for the specified <code>name</code> to the
     * <code>service</code> provided.
     *
     * @param {String} name - the name of the {@link Service} to be managed with <code>name</code>
     * @param {Service} service - the {@link Service} implementation to be managed
     * @throws {Error} If a {@link Service} is already being managed with the same <code>name</code>.
     * @public
     */
    setService(name, service) {
        if (this._services[name]) {
            throw new Error(`Service is already managed with name: ${name}`)
        }

        if (service) {
            this._services[name] = service
        }
    }
}

export default ServiceManager